FIG. 14 illustrates a “contention based Random Access procedure” defined by 3GPP.
Specifically, as illustrated in FIG. 14, in step 1, a mobile station UE transmits “Random Access (RA) Preamble” to a radio base station eNB, and in step 2, the radio base station eNB transmits “Random Access (RA) Response” to the mobile station UE.
In step 3, the mobile station UE transmits “Schedule Transmission” to the radio base station eNB, and in step S4, the radio base station eNB transmits “Contention Resolution” to the mobile station UE.